It is interesting to read others' perspectives on the Proaves network and El Dorado lodge in particular.
The S.O. (She Who Must Be Obeyed) and I spent a week in Colombia in Feb. 2015. We tried to get into El Dorado for three nights, despite the price, but found it was completely booked! I feel this was a considerable loss - we ended up staying in Minca (just down the hill, but hours away on that g-d vile road) at a much cheaper place, but that was not very nice at all. We just had one morning's excursion up to El Dorado, with a jeep and driver (for a truly horrendous sum of money) which was good, but left us wanting more.
Obviously, I don't know what it is like to stay there, but I found the lodge building itself very well kept and comfortable, and they keep a very good cook there - the lunch (which was included in the entrance fee, you have to pay $50 USD to use the trails) was the best meal I had all week. There was a kind of rustic chicken soup with herbs that I really wish I coud have again...
But it's all about the birds, of course - which were fantastic, and (mostly) quite easy to find from the trail system, or indeed, from patio out back! (e.g. Santa Marta Brush-finch foraging on the stairs as we went down to look at the hummingbird feeders.) Unfortunately for us, certain of the Santa Marta endemics are only found higher up than the lodge itself, and so you need to go on an additional excursion for them. This includes a couple of the warblers, which made me very sad I hadn't gotten in there...
While we were in Minca, though, I heard about another lodge that is operating up the road a bit from the El Dorado "turn off", so that might be a potential competitor. Don't remember the name of this lodge, at the moment.